Liquid crystal displays (LCDs) have been widely applied in electrical products. Currently, most of LCDs are backlight type LCDs which comprise a liquid crystal panel and a backlight module.
The LCD panel is composed of two transparent substrates and a liquid crystal layer sealed there-between. In an assembly process of the LCD panel, the liquid crystal layer is filled and sealed between the transparent substrates, thereby forming a liquid crystal cell between the two transparent substrates. The liquid crystal cell is sealed by a sealant between two glass substrates, and the sealant there between is cured to form the LCD panel.
In general, the curing for the sealant is performed by an ultraviolet (UV) lighting machine. The UV lighting machine has UV light lamps arranged densely above the LCD panel for emitting UV light, so as to cure the sealant of the LCD panel.
In some specific LCDs, for example, in polymer stabilized vertical alignment (PSVA) type LCDs, reactive monomers are doped and mixed with liquid crystal molecules in the liquid crystal layer between the two transparent substrates, wherein the a polyimide (PI) is coated on a surface of each of the transparent substrates to act as an alignment layer. When applying a voltage and irradiating UV light to the two transparent substrates, a phase separation arises in the reactive monomers and the liquid crystal molecules, and then a polymer is formed on the alignment layers of the transparent substrates. The liquid crystal molecules are oriented along a direction of the polymer due to the interaction between the polymer and the liquid crystal molecules. Therefore, the liquid crystal molecules between the transparent substrates can have a pre-tilt angle.
Since the reactive monomers doped in the liquid crystal layer of the PSVA type LCD may react with the UV light, when curing the sealant of the PSVA type LCD panel, the liquid crystal of PSVA type LCD panel is required to be shaded from the UV light by a photo-mask. However, in general, portions of the UV light will be reflected by a glass substrate of the photo-mask, and thus it is required to increase an irradiating time or light intensity of the UV light.
As a result, it is necessary to provide a photo-mask and a method for manufacturing the same to solve the problems existing in the conventional technologies, as described above.